Although essentially similar, there are several differences between the two bus implementations. The most significant differences stem from the small form factor, reduced I/O and power requirements of CardBus adapter. A complete PCI implementation includes bus extension pins for 64-bit I/O. Due to the limited number of pins available in the CardBus 68-pin connector, 64-bit address and data paths cannot be implemented; at this time all CardBus devices use 32-bit I/O. Unlike 5V PCI adapters, CardBus peripherals are designed exclusively for use in 3.3V signaling environments.
This applies to: